Second test....

In these last days, I unstitched the purple blocks and the magenta blocks because the purple ones looked too dark. Then I exchanged the colors: purple centers with magenta stripes and magenta centers with purple stripes. This is the result:

Now I have more balance with the colors and I eliminated the part too dark.
But..... I'm still not satisfied!  Game over!
My niece Maira advesed me to lay the blocks like a spiral: it's a good idea and I have to try this way!
Then..... we'll see what will come out!